Answer:
c. temperature and water vapor content is the correct answer.
Step-by-step explanation:
temperature and water vapor content are the two most important in determining the density of air.
When the temperature gets increase it results in the increase of volume and density gets decreases.
Temperature is an important factor to determine the air density.
The concentration of water vapor in the air change depending on where it is placed and so when water vapor is added it will change the density of air because it changes the average mass of air and density gets decrease.